> I intend to add a graph in the inspector's timeline panel that shows the number of global handles for V8. The V8 bindings use maps for WebCore objects to global handles to V8 wrapper objects. A steady increase of global handles is often a sign of a memory leak within v8 bindings.
Are you sure that all wrappers go into a map? What about wrappers for ScriptWrappable objects?
> My question to the JSC folks is, is there a similar counter in JSC? I.e. something that corresponds to the number of wrapped WebCore objects (and potentially other objects that are kept alive without necessarily being reachable from javascript)?
You could read the length of JSC::HandleHeap::m_weakList. Since that's an expensive operation, I'd suggest computing the length during garbage collection and then caching it.
Geoff